Gamemaker
A very popular game creation tool for those who want great flexibility but don't want to spend too long learning to program. Quite powerful, actually, and Kousou Games uses it quite a bit.http://www.gamemaker.nl/

Multimedia Fusision
A more expensive but more proffesional tool, used for game creation and more. Allows you to create a wide variety of games which are more secure than those made with gamemaker, and no programming is required at all. http://www.clickteam.com/English/multimedia_fusion.htm